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Discussion Starter · #1 ·
I'm still not clear on the issue of plum colored blue. I'm going to say what I think I know, and would like you all to either correct me, or go into more detail if possible.

My understanding is the plum color is caused by chemical reaction during the heat process in the blueing phase of production. I'm not sure what the details are here. Maybe it's too much heat or something about the chemical mixture. I also read that die cast parts are more susceptible to the plum coloring. I don't understand why this is.

I also understand this is NOT a detraction from a guns value. As a matter of fact, Rugers are more commonly found with the plum color because Rugers are all die cast parts (I was told). I was also told they are very highly sought after with this plum coloring by serious Ruger collectors.

Now here's another point. A dealer friend told me that the plum coloring can be a sure sign of a re-blue job. So is there any way to discern if the plum coloring was caused by a re-blue, or if it is indeed factory production.

How common is this on Colts? I have a friend (actually he is everyone's friend as a member of this forum) who has a beautiful series 70, almost immaculate in every way, and it has this plum coloring. I think it is beautiful and factory original. All the printing is crisp and clear. No signs I can see at all of a reblue. Maybe if our friend reads this, he will be inclined to post a few pictures so we can talk about the pistol itself in some detail.

I would definitely appreciate any comments to help educate me on this subject.
 

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I think this is the condition you are refering to. It is all original, yet it has a plum colored slide that is associated with a refinished gun. Where are you Mr. Dfariswheel?




 

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My understanding is, that it is in the metal, and even after a rebluing job, if it was plum before, the plum will return.

I have a Ruger Super Blackhawk with a plum frame that is a stunner.
 

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The "plum" or purple color is usually caused by an improperly operated bluing operation.
This can be caused by a tank operated too hot or an improper or "used up" chemical mix.

While some steels are more susceptible to this, no gun maker makes gun parts from metal they KNOW is going to come out with "off" colors.
In any event, if it was the steel ALL of the guns made by that company would be purple.
Since gun companies monitor the type and composition of the steels they buy, this isn't a case of an"off" batch of steel.
Gun companies don't buy steel that is not exactly as specified, and certified as such.

Nor is it a matter of heat treating that's "off". Again, gun companies monitor heat treating with a full range of scientific equipment that leaves nothing to chance.
They DON'T allow bad or even different heat treat guns to be finished, much less to the point of being blued.

The only time I'm aware of this happening was with the early post-1964 Winchester Model 1894's.
Winchester changed to a different steel and heat treat to allow them to lower costs, and the alloy came out of the bluing tank an awful red color.
Winchester had to iron plate the receivers to allow a good blue job until they could solve the problem with the new alloy refusing to blue properly.
A number of gunsmiths had some BAD things to say after doing a re-blue in which unknown to them, they polished off the blue AND the iron plating.
Winchester got an earful about that little surprise.

As for re-blues having a purple color, this is because the bluing operator simply does a bad job.
As above it's improper tank temp or mix.

With many of the "purple" guns, if you take them out in direct sunlight they really have a rather ugly reddish color that only looks purple under other light.

Purple seems to appear on guns in which the process was a LITTLE off, and in processes a LOT off, you get reds.
Since a lot of re-blues were done by local gunsmiths who only fired up the bluing tanks on occasions, they tended to be less then experienced, and allows the process to wonder too much.
When it wondered too far, you got guns that looked OK in the gun shop, but in sunlight had that terrible rusty red color.

My best guess on factory purple guns is that the bluing tank mix gets "used up" and they continue to use it until the color is noticeably off, then they change the tank.
That means that guns run through the tank near the end of the mixes life come out with a slight purple color, and if let go too long, a definite purple to reddish color.

Some guns appear to turn a purple color with time, and I have no idea why this would happen, other than the gun was on the border line of blue and over time continued oxidation of the finish turns it to a purple.

Bottom line is, a purple or reddish color blue job is a sign of a bad blue job.
 

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So, is it safe to say that it is possible to have a factory gun with a off color that has NOT been refinished? But some guns that have a reblue do turn plum if it is a bad mix?
 

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Re: Plum Colored Blue - Revisit Subject for Detail

Or to say the same thing another way, any gun blued with a "bad" mix is subject to becoming plum colored, whether factory or otherwise. One might suspect that refinished guns could be more subject because the operations might be more on again/off again, but that is not necessarily true. A factory may be more "production cost" oriented and squeeze the last out of a process and bigger refinishing shops could tend to run fairly continuosly and focus on that process. Bottom line I believe is: One should look for additional signs of refinishing. Simply being plum is not definitive. :cool:
 

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Re: Plum Colored Blue - Revisit Subject for Detail

Here's some plum coloring on a New Service from a reblue done about 25 years ago.

 

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Good thread! I don't have any plummy Colts yet, but I have several S&Ws with plum. My observation has been I see it most frequently on Model 28s. I wonder if the bluing shop took less care on the economy models. I also have a Model 27 from the early '70s that has barrel and cylinder serial numbers that don't match the frame. Both barrel and cylinder are plum-colored suggesting they may have come off a 28. However, the barrel is 5" which was NOT a 28 length. Just fun to notice and discuss.
 

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H&K P7's and specifically the PSP's are renowned for the ability to turn purple. All three of mine did it. My newest went from blackish to light purple in about 3 years of storage.
 

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In the case of Rugers, it may be in the steel, as each batch is separately "mixed" and as pointed out in RL (the con) Wilsons book of" Bill Ruger : Man and his guns" this is pointed out in detail.
Normally this plum when happens by other makers , if caught in time, will NOT pass inspection (QC) trouble is it may take a bit of time to actually "turn plum" and may have gone out the door, "looking quite blue" and in a period of time , will change. As said above, this is a sign of "improper bath temperature" or again, like in the case of "nickel steel" , like in old Winchester shotguns, high "nickel steel" will turn red (plum). The old timers used to save these guns for the "end of the life" of the bluing salts, so they could 'run up the temperature', as this will "kill the bath" when it is done.
Basically mostly the Ruger collectors find this "plum " color to be "pretty, cute, nice, and/or collectible". Most others figure the gun was "reblued".................
 

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Discussion Starter · #14 ·
Lot's of great information here, and I appreciate everyone's response.

One thing that hasn't been addressed is what I read about the plum coloring being more susceptible to die cast parts. I am certain I read this somewhere, and it stands to reason because it is usually the slide which is a plum color on the Colt autos, and not the rest of the pistol. But I don't understand why this would be.

This is a pretty tricky subject.
 

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I also enjoy old model Rugers, many of which eventually turn 'plum' looking. Some of them are quite striking, with streaks of bright copper color mixed in. On the initial guns, Ruger tried and tried to eliminate the purple color with no success via re-bluing and other means. Finally they gave up and started shipping the guns with a note explaining that customers were indicating that they would rather have the guns in hand than wait for the problem to be fixed. I think of it as Ruger's 'accidental' case-hardened finish.
 

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My '61 Python strangely enough had the plum color on the barrel only. And you could only really see it in bright lighting or in the sunlight. It may have been partially reblued before I got it but now that Colt's has recently redone it in glistening Royal Blue it's a uniform bright blue all over.
 

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Gents,
I have a Colt Junior, Colt mfg. not Astra, which I purchased new in 1971 upon my return from scenic SE Asia. The frame on this is plum. I asked about the color at the time and was told it was due to the alloy of the frame not accepting the blueing well. It is well pocket worn but still a great shooting Colt!
Randy
 

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I have a series '80 Government model that I bought new in the early 80's. The gun is all original and not been refinished. When I purchased it the slide had a beautiful blue color. The slide has since turned to a plum color.

Jnariv
 

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I have a Python with a purple cylinder latch also, mid 1975 or 77, can't remember. I read somewhere they used an outside contractor for those latches who screwed up the bluing.....
 
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